general relativistic astrophysics - Multi-messengaer astrophysics of gravitational wave sources

The direct LIGO/VIRGO detection of gravitational waves (GW) emitted by compact astrophysical objects not only confirmed a key prediction of general relativity but also opens up new opportunities for the investigation of physics and astrophysical in the extreme environments associated with the GW sources. The discovery of the electromagnetic counterpart of GW170817, which was due to a neutron-stars merger firmly established the viability and the importance of time-domain multi-messenger astronomy. GW sources are inhomogeneous classes of objects, and the frequencies/wavelengths of the GW are determined by the linear size of the emitter. As such, the associated physics processes that give rise to the multi-messenger signals would vary substantially among the systems which break the degeneracy of scaling in general
relativity models. For instance, how does a neutron star interact with another neutron star before they undergo merging and how would the resulting black hole interact with the neutron-rich remnant debris after the merging process? What is the physical condition of the neutron-rich matter when two neutron stars are being fused into forming a black hole? How does the electromagnetic radiation that the process generated
is modified when a neutron star is in an in-spiral process into a massive black hole? How would the orbital dynamic of the neutron star be affected by the strong gravitational interaction and the spin-spin and spin-curvature interactions? The student will select one or two related tissues among those mentioned. The objectives are to develop a theoretical framework to model the multi-messenger signatures and to make
predictions that can be tested by current and future instruments. It is phenomenological and theoretical project, emphasis on the astrophysical aspects of gravitational wave research.